Abstract
Climate change is a proven fact. In the report of 2007 from IPCC, one can read that global warming is an issue to be dealt with urgently. In many parts of the world, the estimated rise of temperature (in a very near future) is significant. One of the most affected regions is the Iberian Peninsula, where the increasing need for water will very soon be a problem. Therefore, it is necessary that decision makers are able to decide on all issues related to water management. In this paper, we show a couple of mathematical models that can aid the decision making in the management of an agricultural field at a given location. Having a field, in which different crops can be produced, the solution of the first model indicates the area that should be used for each crop so that the profit is as large as possible, while the water spent is the smallest possible guaranteeing the water requirements of each crop. Using known data for these crops in Portugal, including costs of labour, machines, energy and water, as well as the estimated value of the products obtained, the first mathematical model developed, via optimal control theory, obtains the best management solution. It allows creating different scenarios, thus it can be a valuable tool to help the farmer/decision maker decide the crop and its area to be cultivated. A second mathematical model was developed. It improves the first one, in the sense that it allows considering that water from the rainfall can be collected in a reservoir with a given capacity. The contribution of the collected water from the rainfall in the profit obtained for some different scenarios is also shown.

Abstract

Abstract

Abstract

Abstract
This paper presents CoopREP, a system that provides support for fault replication of concurrent programs based on cooperative recording and partial log combination. CoopREP uses partial logging to reduce the amount of information that a given program instance is required to store to support deterministic replay. This allows reducing substantially the overhead imposed by the instrumentation of the code, but raises the problem of finding a combination of logs capable of replaying the fault. CoopREP tackles this issue by introducing several innovative statistical analysis techniques aimed at guiding the search of the partial logs to be combined and needed for the replay phase. CoopREP has been evaluated using both standard benchmarks for multithreaded applications and real-world applications. The results highlight that CoopREP can successfully replay concurrency bugs involving tens of thousands of memory accesses, while reducing recording overhead with respect to state-of-the-art noncooperative logging schemes by up to 13x (and by 2.4x on average).

Abstract
Computer-based modelling tools allow students to express their theories in models that can be simulated. In this way, students can use their theories operationally, confronting themselves with the consequences of their ideas. The ability of students to form and express a mental model will be expanded if they are given an opportunity to become aware of their own mental model by expressing this same model and comparing it to other models, like a consensus model. The building of numerical models of biophysical phenomena, such as the mechanics of breathing, or blood circulation, has the potential for student motivation as well as long-term learning. Our theory is that by re-building well known numerical models of physiological phenomena students will have the opportunity to change their perceptions about the relevance of the contents addressed, simultaneously improving their learning in the topics covered and increasing their motivation in the basic science disciplines in their curricula. For the implementation of computer numerical models historically it was necessary to use some programming language, such as MATLAB, BASIC, C++, JAVA. With the development of computer science, it is now possible to these students "construct" models of physical phenomena expressed through dedicated computer tools without necessarily having to do so in a programming language. As for example we have STELLA, MODELLUS, or STARLOGO. There is also the possibility of using a spreadsheet such as Microsoft EXCEL, Open Office CALC, Google SHEETS, or others, as tools that allow students to express physical models. The current spreadsheets, even those available for free, are very powerful, having many integrated tools, in terms of calculation, and we can count on several other features, such as graphs of various types, buttons and other tools that allow interaction with the model, and databases that can be integrated into the spreadsheet. There are several advantages of using spreadsheets in science education due to its general access, through smartphones, tablet's and computers, ease of implementation for the basic operations, and ease of the "debug" process, relative to other types of software. Also, it does not require prior knowledge of programming languages, or about complex mathematical software, which would an obstacle to the learning in itself. There is also the positive side effect of learning how to use a spreadsheet that is a plus in itself for the future professional's. This paper will have a review of the state of the art of using spreadsheets in Modelling Based Learning. Also, it will be presented a study with first year undergraduate students of a health care course, using Biophysical models historically very important in the physiology and medicine development.